1. Field of the Invention
The present invention relates to a resist stripping composition for use in the production of semiconductor integrated circuits, and more particularly, to a resist stripping composition for removing resist residues remaining after etching or ashing.
2. Description of the Prior Art
Semiconductor devices such as IC and LSI, and liquid crystal panel elements have been generally produced by the steps of forming a photoresist film on an inorganic substrate; patterning the photoresist film by exposure to light and subsequent development; dry-etching unmasked portion of the inorganic substrate with a reactive gas using the patterned photoresist film as a mask; ashing the photoresist film; and removing the photoresist residues (protective deposition film) from the inorganic substrate. Since the dry-etching of the inorganic substrate through the patterned photoresist film has been usually performed using a halogen-based reactive gas, undesired resist (photoresist) residues result from the reaction between the halogen-based reactive gas and the resist. The resist residues tend to cause various troubles such as open circuit and abnormal wiring and, therefore, must be completely removed.
Conventionally, alkaline stripping solutions have been generally used to remove the resist residues. As the alkaline stripping solutions, proposed are a stripping solution containing an alkanol amine or an ethylene oxide adduct of a polyalkylene polyamine, a sulfone compound and a glycol monoalkyl ether (Japanese Patent Applications Laid-Open No. 62-49355); a stripping solution containing dimethylsulfoxide as a main ingredient, a diethyleneglycol monoalkyl ether and a nitrogen-containing organic hydroxy compound (Japanese Patent Applications Laid-Open No.64-42653); and the like. These alkaline stripping solutions, however, show alkaline nature due to amine liberated from the adduct by the action of water absorbed during the use, or show alkaline nature during washing after the stripping treatment if the washing is made using water instead of using an organic solvent such as alcohol, thereby likely to cause severe corrosion of aluminum, etc. widely used as materials for forming fine wirings. Therefore, the known stripping solutions are unsuitable for use in micro-processing techniques requiring a recent strict dimensional accuracy.
Recently, an aqueous solution containing a fluorine compound, amide, dimethylsulfoxide (DMSO) solvent and a corrosion inhibitor comes into use as the resist stripping solution due to its high stripping capability and easiness to use (Japanese Patent Application Laid-Open No. 8-202052 and U.S. Pat. No. 5,962,385). However, these fluorine-based resist stripping solutions corrode wiring made of aluminum during rinsing with water after the stripping treatment. Namely, these stripping solutions are highly corrosive to the wiring materials when diluted with water. In addition, the fluorine compound deposits when the fluorine-based resist stripping solutions are rinsed with an organic solvent. Therefore, the removal of resist residues is insufficient merely by rinsing the fluorine-based resist stripping solutions with an organic solvent after the stripping treatment.
The present invention has been made to solve the above problems in the prior art, namely, an object of the present invention is to provide a resist stripping composition which completely removes resist residues remaining after etching or ashing in a wiring process for manufacturing semiconductor devices such as IC and LSI or liquid crystal panel elements, at a low temperature in a short period of time without causing corrosion of the wiring materials during the rinse. Another object of the present invention is to provide a process for producing a semiconductor device, the process including a rinsing treatment of the semiconductor device with a rinsing solution after the treatment with the resist stripping composition.
As a result of extensive studies in view of the above objects, the present inventors have found that an aqueous solution containing 0.001 to 0.5% by weight of a fluorine compound and 50 to 99% by weight, particularly 81 to 99% by weight of an ether solvent is suitable as the resist stripping composition because it quite easily removes resist residues remaining after etching or ashing without any corrosion of the wiring materials, etc. and also causes no corrosion of the wiring during the rinsing after the treatment with the aqueous solution. The present invention has been accomplished based on this finding.
Thus, the present invention provides a resist stripping composition comprising 0.001 to 0.5% by weight of a fluorine compound and 50 to 99% by weight of an ether solvent, the balance being substantially water.
The present invention further provides a process for producing a semiconductor device, comprising the steps of (1) forming a resist film on a thin conductive film deposited on an inorganic substrate, (2) patterning the resist film, (3) etching the thin conductive film using the patterned resin film as a mask, (4) removing resist residues remaining after the etching by contacting the resist residues with the resist stripping composition mentioned above, and (5) rinsing the resultant device with a water-soluble organic solvent or a mixed solvent of the water-soluble organic solvent and water.
The present invention still further provides a process for producing a semiconductor device, comprising the steps of (1) forming a resist film on a thin conductive film deposited on an inorganic substrate, (2) patterning said resist film, (3) etching the thin conductive film using the patterned resist film as a mask, (4) ashing the patterned resist film, (5) removing resist residues remaining after the ashing by contacting the resist residues with the resist stripping composition mentioned above, and (6) rinsing the resultant device with a water-soluble organic solvent or a mixed solvent of the water-soluble organic solvent and water.